1
JEE Main 2021 (Online) 27th August Morning Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
There are 1010 radioactive nuclei in a given radioactive element, its half-life time is 1 minute. How many nuclei will remain after 30 seconds? $$\left( {\sqrt 2 = 1.414} \right)$$
A
2 $$\times$$ 1010
B
7 $$\times$$ 109
C
105
D
4 $$\times$$ 1010
2
JEE Main 2021 (Online) 27th August Morning Shift
MCQ (Single Correct Answer)
+4
-1
Which of the following is not a dimensionless quantity?
A
Relative magnetic permeability ($$\mu$$r)
B
Power factor
C
Permeability of free space ($$\mu$$0)
D
Quality factor
3
JEE Main 2021 (Online) 27th August Morning Shift
MCQ (Single Correct Answer)
+4
-1
If E and H represents the intensity of electric field and magnetising field respectively, then the unit of E/H will be :
A
ohm
B
mho
C
joule
D
newton
4
JEE Main 2021 (Online) 27th August Morning Shift
MCQ (Single Correct Answer)
+4
-1
The resultant of these forces $$\overrightarrow {OP} ,\overrightarrow {OQ} ,\overrightarrow {OR} ,\overrightarrow {OS} $$ and $$\overrightarrow {OT} $$ is approximately .......... N.

[Take $$\sqrt 3 = 1.7$$, $$\sqrt 2 = 1.4$$ Given $$\widehat i$$ and $$\widehat j$$ unit vectors along x, y axis]

JEE Main 2021 (Online) 27th August Morning Shift Physics - Vector Algebra Question 15 English
A
$$9.25\widehat i + 5\widehat j$$
B
$$3\widehat i + 15\widehat j$$
C
$$2.5\widehat i - 14.5\widehat j$$
D
$$ - 1.5\widehat i - 15.5\widehat j$$
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